Attendances at Women's Super League matches last season increased more than 30% on the previous term, with the average attendance in 2014 up to 728. Manchester City recorded the highest average league attendances of the season at 949.

"This year has arguably been the most competitive FA WSL season to date and promotion and relegation has certainly played a big part in that," said FA director of the national game and women's football Kelly Simmons.

"Increasing the number of promotion spots not only opens up more opportunity for clubs but will also help to drive the standard of FA WSL 2 which can only benefit the women's game."

The 2015 WSL season begins in March with fixtures expected to be announced in the New Year.